Sum of values in an array that are larger than a certain number?

I'm trying to get my program to add up all of the values greater than integer x in the array so I can find their average. The following keeps giving me ridiculously large numbers:

 for (int index = 0; index < 10; index++)
    {
        if (num[index] > x)
        {
            amountlarger++; //amount of numbers > x
            sum2 = sum2 + num[index];
        }
    }

When I ask it to divide sum2 by amountlarger the math works fine, the calculated average is just far larger than it should be.